The present invention relates to phonograph cartridge styli and more particularly to a stylus for playing back the matrix or stamper with which phonograph records are stamped.
The first step in the production of phonograph records comprises the cutting of a master. The master is then used to produce a metal matrix which is the negative of the master and used to produce a metal mother. From the metal mother, stampers are formed which are duplicates of the matrix. The matrix and stampers are the negative or reverse of the master to the extent that grooves in the master become raised ridges in the stamper and vice-versa. The stamper is formed of a relatively hard metal and it in turn is then used with another stamper representing the other side of the record as a die into which vinyl material is introduced and squeezed under extremely high pressure to form the final phonograph record platter.
It can thus be seen that the resultant final record disc can only be as good as the stamper. Heretofore, means have been available to play back the master, mother and final record but not the stamper or matrix. It was necessary to produce records from a stamper and then play back the records in order to test the accuracy of the stamper, requiring as a result the expenditure of time and labor. If the produced record did not play back true, it was then necessary to determine whether the problem was in the stamper or record. Further, if the problem was in the stamper, as for example, a high spot or rough spot, it was difficult to pinpoint the location of the problem area for correction.
In view of the above, it is the principal object of the present invention to provide an improved phonograph cartridge stylus specifically adapted to permit the playback of phonograph record stampers.
A further object is to provide such a stylus which may be utilized in a conventional phonograph cartridge.
A still further object is to provide such a stylus which, while playing the master can also serve to remove or polish down high or rough spots.